An electrical dimmer device and its driving method applicable to, for example, an image pickup unit and a display unit operate so that when a control signal for stop adjustment is changed from its current value of stop adjustment to a larger value, which occurs when the light transmissivity of a positive type liquid crystal is raised, or when the light transmissivity of a negative type liquid crystal is lowered, the control signal is temporarily varied to an intermediate value that is larger than the larger value. The energy of the varied larger value and a time during which that varied value is applied are determined in accordance with predetermined values. By doing so, it is possible to make a response speed when changing the light transmissivity extremely faster and thus attain a response time, of for example, one field period of time or less required for a stop mechanism of a video camera.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An electrical dimmer device including a liquid crystal whose light transmissivity is controlled by an energy of an electric signal supplied thereto, the device comprising driving means for varying the energy of the electric signal that controls the light transmissivity of the liquid crystald, and operation signal receiving means for receiving an operation signal for a stop adjustment, wherein, when the operation signal for a stop adjustment is received, the driving means varies the energy of the electric signal according to a current value and a received value of the operation signal for the stop adjustment, and wherein, when the light transmissivity is changed from its current value to a desired value, the driving means varies the energy of the electric signal to a greater extent than a change width corresponding to the change of the light transmissivity for a predetermined time before varying the energy to that corresponding to the desired value of the light transmissivity.
2. The electrical dimmer device according to claim 1 , wherein said driving means varies the energy of the electric signal by changing the voltage of a control signal.
3. The electrical dimmer device according to claim 2 , further comprising means for determining a level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage is applied depending on values of respective voltages before varying the voltage and after varying the voltage.
4. The electrical dimmer device according to claim 3 , wherein the level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage is applied are determined using a table that contains respective voltage values before varying the voltage and after varying the voltage as reference values.
5. The electrical dimmer device according to claim 4 , further comprising means for measuring an environmental temperature and changing over the value in the table depending on a measured environment temperature.
6. The electrical dimmer device according to claim 3 , wherein said means for determining the level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage is applied operates so that a response time when lowering the light transmissivity from the current value is equal to or less than one field period of time.
7. The electrical dimmer device according to claim 3 , wherein said means for determining the level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage is applied operates so that a response time when raising the light transmissivity from the current value is equal to or less than one field period of time.
8. The electrical dimmer device according to claim 1 , wherein said driving means varies the energy of the electric signal by changing a pulse width of the control signal.
9. The electrical dimmer device according to claim 8 , where said driving means includes means for determining a value of the pulse width to which the pulse width is varied once and the predetermined time during which the varied pulse width is interposed depending on values of the respective pulse widths before varying the pulse width and after varying the pulse width.
10. The electrical dimmer device according to claim 9 , wherein said means determining the value of the pulse width to be varied once and the predetermined time during which that varied pulse width is interposed uses a table that contains the values of the respective pulse widths before varying the pulse width and after varying the pulse width as reference values.
11. The electrical dimmer device according to claim 10 , further comprising means for measuring an environmental temperature and changing over the values in the table depending on a measured environmental temperature.
12. The electrical dimmer device according to claim 9 , wherein said means for determining the value of the pulse width to be varied once and the predetermined time during which the varied pulse width is interposed operates so that a response time when lowering the light transmissivity from the current value is equal to or less than one field period of time.
13. The electrical dimmer device according to claim 9 , wherein said means for determining the value of the pulse width to be varied once and the predetermined time during which the varied pulse width is applied operates so that a response time when raising the light transmissivity from the current value is equal to or less than one field period of time.
14. The electrical dimmer device according to claim 1 , wherein the liquid crystal is a guest-host type liquid crystal that contains dichromatic dye molecules.
15. A driving method for an electrical dimmer device including a liquid crystal whose light transmissivity that is controlled by energy of an electric signal supplied thereto, characterized by varying the energy of the electric signal that controls the light transmissivity of the liquid crystal, wherein, when the light transmissivity is changed from its current value to a desired value, the driving means varies the energy of the electric signal to a greater extent than a change width corresponding to the change of the light transmissivity for a predetermined time before varying the energy to that corresponding to the desired value of the light transmissivity.
16. The driving method of an electrical dimmer device according to claim 15 , the energy of the electric signal is changed in accordance with a change of the voltage of a control signal.
17. The driving method of an electrical dimmer device according to claim 16 , further comprising determining a level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage is applied depending on values of the respective voltages before varying the voltage and after varying the voltage.
18. The driving method of an electrical dimmer device according to claim 17 , wherein said determining the level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage in applied includes using a table that contains the values of the respective voltages before varying the voltage and after varying the voltage as reference values.
19. The driving method of an electrical dimmer device according to claim 18 , further comprising measuring an environmental temperature and changing over the values in the table depending on a measured environmental temperature.
20. The driving method of a electrical dimmer device according to claim 17 , wherein said determining the level of the voltage to which the voltage is varied once and the predetermined time during which that varied voltage is applied is performed so that a response time when lowering the light transmissivity from the current value is equal to or less than on field period of time.
21. The driving method of an electrical dimmer device according to claim 17 , wherein said determining the level of the voltage to which the voltage is varied once and the predetermined time during which the varied voltage is applied is performed so that a response time when raising the light transmissivity from the current value is equal to or less than one field period or time.
22. The driving method of an electrical dimmer device according to claim 15 , wherein the energy of the electric signal is accomplished by changing a pulse width of a control signal.
23. The driving method of an electrical dimmer device according to claim 22 , wherein said determining value of the pulse width to be varied once and the predetermined time during which that varied pulse width is interposed depends on a value of the pulse widths before varying the pulse width and after varying the pulse width.
24. The driving method of an electrical dimmer device according to claim 23 , wherein said determining the value of the pulse width to be varied once and the predetermined time during which that varied pulse width is interposed uses a table that contains the values of the pulse widths before varying the pulse width and after varying the pulse width as reference values.
25. The driving method of an electrical dimmer device according to claim 24 , further comprising measuring an environmental temperature and changing over the values in the table depending on a measured environmental temperature.
26. The driving method of an electrical dimmer device according to claim 23 , wherein said determining the value of the pulse width to be varied once and the predetermined time during which that varied pulse width is interposed is performed so that a response time when lowering the light transmissivity from the current value is equal to or less than one field period of time.
27. The driving method of an electrical dimmer device according to claim 23 , wherein said determining the value of the pulse width to be varied once and the predetermined time during which that varied pulse width is interposed is performed so that a response time when raising the light transmissivity from the current value is equal to or less than one field period of time.
28. The driving method of an electrical dimmer device according to claim 15 , wherein the liquid crystal is a guest-host type liquid crystal that contains dichromatic dye molecules.
29. An imaging apparatus comprising: an imaging unit that captures an image; a liquid crystal unit that controls light inputted to the imaging unit; and an energy control unit that controls light transmissivity of the liquid crystal unit by varying an energy of an electric signal, wherein, when the light transmissivity of the liquid crystal unit is changed from its current value to a desired value, the energy control unit varies the energy of the electric signal to a greater extent than a change width corresponding to the change of the light transmissivity for a predetermined time before varying the energy to that corresponding to the desired value of the light transmissivity.
30. The imaging apparatus according to claim 29 , wherein the energy control unit varies the energy of the electric signal by changing the voltage of a control signal fed to the liquid crystal unit.
31. The imaging apparatus according to claim 29 , wherein the energy control unit varies the energy of the electric signal by changing a pulse width of a control signal fed to the liquid crystal unit.
32. The imaging apparatus according to claim 29 , wherein the liquid crystal unit comprises a guest-host type liquid crystal that contains dichromatic dye molecules.
33. A method of controlling a light adjusting device of an imaging apparatus, the method characterized by: providing a liquid crystal unit that controls light input to an imaging unit that captures an image controlling a light transmissivity of the liquid crystal unit by varying an energy of an electric signal, wherein, when the light transmissivity of the liquid crystal unit is changed from its current value to a desired value, the step of varying varies the energy of the electric signal to a greater extent than a change width corresponding to the change of the light transmissivity for a predetermined time before varying the energy to that corresponding to the desired value of the light transmissivity.
34. The method of controlling a light adjusting device of an imaging apparatus according to claim 33 , wherein in the step of varying the energy of the electric signal is varied in accordance with a change of the voltage of a control signal fed to the liquid crystal unit.
35. The method of controlling a light adjusting device of an imaging apparatus according to claim 33 , wherein in the step of varying the energy of the electric signal is varied by changing a pulse width of a control signal fed to the liquid crystal unit.
36. The method of controlling a light adjusting device of an imaging apparatus according to claim 33 , wherein the step of providing includes providing a guesthost type liquid crystal that contains dichromatic dye molecules.
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April 19, 2002
June 12, 2007
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